Flexible couplings



June 28, 1966 L. P. CROSET 3,257,825

FLEXIBLE COUPLINGS Filed March 6. 1964 100/; PM; Geasrr 3,257,825 Patented June 28, 1966 United States Patent Office 3,257,825 FLEXIBLE COUPLINGS Louis Paul Croset, Im Schleipfenacker 10, Forch, Zurich, Switzerland Filed Mar. 6, 1964, Ser. No. 349,824

Claims priority, application Great Britain, Mar. 14, 1963,

10,137 63 4 Claims. (Cl. 64-14) This invention relates to flexible vibration damping spondingly lower coupling stiflness.

the blocks operate in pairs, one driving, one trailing, for

any direction of rotation, is to base the coupling characteristics, namely stiffness and torsional deflection, not by a haphazard choice of the number of cells, but by the calculation of the desired number of cells which determines the angle of torsional deflection as a function of the cell angle for any specific mass-elastic system, the size or diameter of the blocks and the number of blocks per cell being determined by the desired coupling capacity.

According to the invention, a flexible vibration damping apparatus comprises two coaxial members, two sets of blades which extend radially and axially of the apparatus and which blades are connected alternately to said coaxial members so as to form cells, a plurality of solid circular blocks of elastic material in each cell, the blocks having circular flat end surfaces parallel to each other of smaller diameter than that of the blocks, an outer circular peripheral surface of smaller width than that of the blocks,

and inclined outer annular surfaces from the end faces of the peripheral surface.

The term solid is intended to mean that the blocks are free from any major holes or cavities, e.g. no bolts,

pins or the like pass through the 'blocks and in fact the blocks should even be as free as possible from smaller cavities although in practice it may be impossible to avoid occasional minor cavities altogether.

For blocks having a diameter D, the width may be 0.45 to 0.55' D, and the blocks may have an end surface diameter of 0.5 to 0.6 D (preferably 0.45 to 0.55) and a width of peripheral surface 0.2 to 0.3 D.

The size of blocks is preferably such as to fit the cells Without pre-compression or such as to require up to 3.0 percent (preferably not more than 1.5 percent) pre-compression in both diameter and width.

Each'cell may contain 2 to 6 blocks.

The roots of the blades may have a radius equal to half the radial height of the cells and the remainder of the blades may have their sides parallel to each other.

The cone-shape block ofiers the following advantages:

(a) Softer effect than cylindrical blocks;

(b) Area of contact with cell end-walls is less than 50% of that of cylindrical blocks used hitherto;

(c) Lesser volume of rubber and simple mould shape.

A constructional form of the invention is illustrated by Way of example in'the accompanying drawing.

FIGURE 1 is a half sectional view on a radial plane I-I of a coupling made in accordance with the invention; and

FIGURE 2 is a half end view thereof with the end' plate removed.

The two coaxial members consist of an inner member 10 carrying blades 11 surrounded by an outer member 12 carrying blades 13. The outermember 12 is bolted by bolts 14 to a driving flange 16 on a driving sleeve 17. Each blade on one member is located normally midway between two blades on the other member to form cells. A shows'the cell angle and B, shows the centre of blade angle, both angles being identical.

Each cell contains three solid rubber blocks and the cells and closed by an end plate 18 bolted by bolts 19 to the member 12. Each block has an outer peripheral surface 22 two circular end surfaces 23, 24 and two frustoconical surfaces 26, 27 connecting the surface 22 to the end surfaces 23, 24. For a block diameter D the width W of the block is 0.5 D, the diameter E of end face 0.55 D, and the width P of the peripheral surface 0.25 D. The end surfaces contact each other and/or the flange 16 or plate 18. The roots of the blades are curved to a radius equal to half the radial height of the cells.

The number of cells may vary for example between 6 and 16 and it will be realised that in a coupling having 6 cavities only the cavity angle will be 60 and in a coupling with 16 cavities 22.5 so that for a given maximum compressive strain of say 25% the appropriate torsional deflection angles obtained would be 15 and 5.6, respectively.

The preferred number of blocks in each cell is 2, 3, or 5 but it is also possible to make a coupling with only 1 block or if desired 6 blocks per cavity.

The blocks whether driving or trailing at all times make contact with the parts 16, 18 with a pre-compression of the order of 1 to 1.5% to ensure that the blocks are maintained in their true plane of rotation at all times and cannot possibly twist in the cavities. In other words, only the block end-faces contact the cell end walls, both under no-load and under full-load conditions, in order to reduce the friction between the driving blocks and the cavity walls. Whilst under maximum torque load the driving block end-faces become slightly elliptical, the conical flanks 26, 27 remain out of contact with the cavity walls at all times and an increase in the block deformation of the order of is thereby obtained compared with the cylindrical blocks.

The blades may if desired by slightly tapered.

The use of tapered instead of parallel blades makes the cell volume a little larger, obtaining thereby an increased torsional flexibility of the coupling and incidentally effecting a reduction in weight. The increase in torsional flexibility is of the order of 5%.

I claim:

1. A flexible vibration damping apparatus comprising two coaxial members, two sets of'blades which extend radially and axially of the apparatus and-which blades are connected alternately to said coaxial members so as to form cells, a plurality of solid circular blocks of of said blocks having a width 0.45 to 0.55 D, an end surface diameter 0.5 to 0.6 D and a width of peripheral surface 0.2 to 0.3 D.

2. A flexible vibration damping apparatus comprising two coaxial members, two sets of bladeswhich extend radially and axially of the apparatus and which blades are connected alternately to said coaxial members so as t to form 6 to 16 cells at least two and not more than six solid circular blocks of elastic material in each cell, the blocks having circular fiat end surfaces parallel to each other of smaller diameter than that of the blocks, an outer circular peripheral surface of smaller width than that of the blocks, and inclined outer annular surfaces from the end faces to the peripheral surface, said blocks having a diameter D, each of said blocks having a width of 0.45 to 0.55 D, an end surface diameter of 0.5 to 0.6 D, and a Width of peripheral surface 0.2 to 0.3 D.

3. A damping apparatus as claimed in claim 1 wherein the blocks fit in the cells without rare-compression or with a pre-compression not exceeding 3.0 percent in diameter and width.

the roots of the blades have a radius equal to half the radial height of the cells and the remainder of the blades have their sides parallel to each other.

References Cited by the Examiner UNITED STATES PATENTS BROUGHTON G. DURHAM, Primary Examiner.

4. A damping apparatus as claimedin claim 1 wherein H C (1015, A i t Examiner, 

1. A FLEXIBLE VIBRATION DAMPING APPARATUS COMPRISING TWO COAXIAL MEMBERS, TWO SETS OF BLADES WHICH EXTEND RADIALLY AND AXIALLY OF THE APPARATUS AND WHICH BLADES ARE CONNECTED ALTERNATELY TO SAID COAXIAL MEMBERS SO AS TO FORM CELLS, A PLURALITY OF SOLID CIRCULAR BLOCKS OF ELASTIC MATERIAL IN EACH CELL, THE BLOCKS HAVING CIRCULAR FLAT END SURFACES PARALLEL TO EACH OTHER OF SMALLER DIAMETER THAN THAT OF THE BLOCKS, AN OUTER CIRCULAR PERIPHERAL SURFACE OF SMALLER WIDTH THAN THAT OF THE BLOCKS, AND INCLINED OUTER ANNULAR SURFACES FROM THE END FACES TO THE PERIPHERAL SURFACE, SAID BLOCKS HAVING A DIAMETER D, EACH OF SAID BLOCKS HAVING A WIDTH 0.45 TO 0.55 D, AN END SURFACE DIAMETER 0.5 TO 0.6 D AND A WIDTH OF PERIPHERAL SURFACE 0.2 TO 0.3 D. 